Newman

Description from extension meta

Get simple notifications when a new gmail message arrives.

Image from store

Description from storeGet a notification if you got an email on your gmail account since the last time you checked (visited your inbox), without constant interruptions or counts of thousands of unread messages.
Usage:
-If there are no new messages the extension icon shows a blank page.
-If a message arrived the icon will turn into a red paper plane.
-You can go to your inbox by clicking the extension icon.
-The icon will only show a paper plane if something new arrived since the last time you visited gmail.
Notes:
-The extension doesn't show the unread count (this is on purpose and meant to be a feature).
-You must be logged in gmail for the extension to work. If you aren't it will show a greyed icon with an "X".
Other works
http://imagentleman.github.io